Q1. How do I prevent the staircase effect?
A1. The staircase effect is caused by the way some printers expect lines to
be terminated. Some printers want lines that end with a carriage-return/line-feed
sequence (DOS-style) instead of the default line-feed sequence used
for UNIX-type systems. The easiest way to fix this is to see if your printer
can switch between the two styles somehow---either by flipping a DIP switch, or
by sending an escape sequence at the start of each print job. To do the latter,
you need to create a filter (see Q2 and
A quick fix is to use a filter on the command-line. An example of this might be
$ cat thesis.txt | todos | lpr
Q2. What is a filter?
A2. A filter is a program that reads from standard input (stdin), performs some action on this input, and writes to standard output (stdout). Filters are used for a lot of things, including text processing.
Q3. What is a magic filter?
A3. A magic filter is a filter that performs an action based on a file's type. For example, if the file is a plain, text file, it would simply print the file using the normal methods. If the file is a PostScript file, or any other format, it would print it using another method (ghostscript).